How does selection shape genetic variation?
Before you understand evolution, you must understand the molecule that mutates: DNA.
Q1: Two genes are said to be “linked” if they are:
Answer: B Explanation: Linkage is physical proximity on the same chromosome. Far apart genes act like they are unlinked due to crossing over.
Q2: If 20% of offspring from a test cross are recombinant, the map distance between the two genes is:
Answer: B (20 cM) Explanation: 1% recombination = 1 centiMorgan (cM). So 20% = 20 cM.
Q3: Crossing over occurs during which stage of meiosis?
Answer: A (Prophase I) Explanation: Specifically during the pachytene stage when homologous chromosomes pair up as bivalents. introduction to genetics and evolution coursera quiz answers
Q4: You observe 40 recombinant offspring and 160 parental offspring out of 200 total. What is the recombination frequency?
Answer: B (20%) Explanation: 40 / 200 = 0.20 = 20%.
Q5: A three-point test cross is superior to two-point crosses because it:
Answer: B Explanation: Double crossovers make two distant genes appear closer. Three-point crosses correct for this.
Q1: A mutation changes a codon from UAC (Tyrosine) to UAU (Tyrosine). This is an example of:
Q2: A frameshift mutation is most likely caused by:
Q3: Which of the following is true regarding transcription? How does selection shape genetic variation
Q4: A nonsense mutation results in:
Advanced Question: If a DNA sequence is 5'-ATGC-3' on the coding strand, what is the mRNA sequence?
This is where students often stumble. We move beyond simple dominance to epistasis, polygenic traits, and gene linkage.
In conclusion, the "Introduction to Genetics and Evolution" course on Coursera provides a comprehensive overview of the fundamental principles of genetics and evolution. By reviewing the course materials, practicing with quizzes and assessments, and seeking help when needed, you can gain a deeper understanding of these complex topics.
Hope you found this information helpful. Let me know if you have any further questions or if there's anything else I can help with.
Q1: The Biological Species Concept defines a species as:
Answer: C Explanation: Ernst Mayr’s definition. Key phrase: “reproductively isolated.” Answer: B Explanation: Linkage is physical proximity on
Q2: Which of the following is a pre-zygotic reproductive barrier?
Answer: C Explanation: Pre-zygotic barriers act before fertilization. Temporal isolation prevents mating. The others are post-zygotic.
Q3: In a phylogenetic tree, the point where a single lineage splits into two is called a:
Answer: A (Node) Explanation: Nodes represent the most recent common ancestor of the descendant lineages.
Q4: A monophyletic group (clade) includes:
Answer: B Explanation: This is the definition of a true clade (a “natural” group in evolution).
Q5: Which type of mutations are most useful for comparing closely related species?
Answer: B Explanation: Closely related species have few differences, so you need a fast-evolving region (like mtDNA) to see variation. Slow-evolving genes (like rRNA) are used for distantly related species.
How one species becomes two, and how we reconstruct evolutionary history.